FIGURE 1.

Medicago truncatula metal tolerance protein 2 (MtMTP2), a member of the MTP protein family, is highly expressed in the nodule. (A) MtMTP2 expression in nitrogen-fertilized and 28 dpi nodulated M. truncatula plants relative to the internal standard gene Ubiquitin carboxyl-terminal hydrolase. Values with different letters are significantly different (Tukey’s HSD p < 0.05; n = 4). (B) Unrooted phylogenetic tree of the plant metal tolerance protein family. (C) Tertiary structure model of MtMTP2 and its template YiiP (3h90). Positions of metal coordinating amino acids and Zn(II) elements are indicated. (D) Alignment of the conserved amino acids in MTP members. The amino acid sequences were aligned using the ClustalW method.